Loop-spreader mechanism for sewing machines



MQKOHLER June 4; 1929.

' LOOP SPREADER MECHANISM FOR SEWING MACHINES Filed Feb. 12, 1927 4 Sheets-Sheet June 4, 1929. M. Kbi-ILER LOQP SPREADER MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 2 Filed Feb. 12, 192'! W x INVENTOR BY yr/lwz/ v ATIO June 4, 1929. M. KOHLER 71,715,370

LOOP EPREADER MECHANISM FOR SEWING MACHINES Filed Feb. 12, 1927 4 Sheets-Sheet 5 INVENTOR W /%zM/- /4.' A'ITORN Y Juzie4, 1929. M. KCJHLER 1,715,370

LObP SPREADER MECHANI SM FOR SEWING MACHINES Filed Feb .12, 1927 4 Sheets-Sheet 4 ATTORNEY Patented June 4, 1929.

UNITED] STATES PATENT- OFFICE.

MAX KbHLEB, OF LIMBACH, GERMANY.

LOOP-SPREADER MECHANISM FOR SEWING MACHINES.

Application filed February 12, 1927. Serial No. 167,627.

The present invention relates to an improvement in sewing machines more particularly of the ovcrseaming type. One object has been to improve the operation of such a machine by eliminating one of the frequent causes of inaccurate operation, namely, the dropping of a stitch or loop by reason of failure of the needle to pass between the looper and the looper thread.- A well known expedient in the art is avso-called loop spreader but, it is not believed that the Spreaders thus far evolved have operated.

for effective loop-forming co-operation with 2 the needle.

One embodiment of my invention is illustrated in the drawings accompanying the present specification and in which Figure 1 is a side elevation with a portion a of the housing cut away to disclose the needle and looper actuating mechanism,

Figure 2 a side view in detail showing the relative positions of the needle, looper, and loop spreader when the needle is in its extreme forward position, v

Figure 3 a front view in detail of the needle, looper, and loop spreader in the relative positions indicated in Figure 2,

Figure l a side view in detail showing the I relative positions of the needle, looper, and

loop spreader when the needle is moving marwar'dly.

Figure 5 a front view in detail of the needle, looper, and loop spreader in the relative positions indicated in Figure'4,

' Figure 6 a front view in detail showing the relative positions of the needle, looper, and loop spreader when the needle is about to move forward into position between the looper and the looper thread, and

Figure 7 a detail view in perspective of the needle, looper, and 100 er thread in the relative positions indicate in Fi re '6.

In the embodiment of m lnvention illustrated in the drawings t e loop forming chine (performin mechanism is mounted in a casing 1 provided with a main or driving shaft 2. The formatlon of the loops is accomplished by means of a needle 3, carrying athread 4, and alooper 5 carrying athread' 6. The needle 3 is mounted on a needle bar 7 mounted in spaced brackets 8 and 9 within the housing land actuated by any suitable connection with the drivlng shaft 2, not shown.

The looper 5 is mounted ona looper rod 19 rotatable in a carrier 10 to which is imparted a combined to-and-fro and up-anddown motion by means of suitable connections with the main shaft 2. These connections include a rod 11 actuated by a cam, not shown, mounted on shaft 2 and engaging one end of a bell crank lever 12 journaled at 13, the other end of which is plvotally secured to the carrier 10 at 14. The up-and-down and to-and-fro movement of looper carrier 10 is also in part effected by means of a rod 15 cooperating with an eccentric cam not shown and mounted on shaft 2, said rod 15 effecting rocking movement of a lever 16 journaled at 17 and pivotally connected with the carrier 10 by means of alink 18. The

mechanism herelnabove described in connec tion with the combined to-and-fro and u and-down motion of the looper'carrier is su stantially the same as that described in detail and shown in m. co-pending application, Serial No. 37,916, fi ed June 18, 1925.

As indicated in Figure 1 of the drawings,

looper rod 19 is mounted to rotate in the carrier 10, rotation thereof. being effected by means of a rod 20 cooperating with an cecentric on shaft 2, not shown. ,The looper rod.19 is connected to rod 20 by a ball and socket joint 21 formed at the end of a short lever extending from the interior and of looper rod 19. Thus, the up-and-down motion of rod 20 is transmitted through the short lever to produce a rotating or twisting movement of the looper rod '19relative1yto the carrier 10.. r My present invention as applied to a mathe operations above describe has to o more particularly with control of the thread at the 'point where the looper and the'needle cooperate to form the stitch or loop. For this pur ose, a collar 22 is secured to the looper m 19 and rotates therewith. A lever 23 forms part of or is secured to the collar 22. A bracket 24 is mounted on carrier 10 and provides a suitable bearing for a loop spreader having a shank 25 with a thread engaging notch 26 at its lower or free end. The upper end is provided with a lever 27, which is connected to lever 23 by means of a link 28.

In operation, the needle 3 moves forward and back in synchronized relation with the combined movements of the looper, as is Well known in the art, to form the loops or stitches. Assuming that the loop forming elements are in the positions shown in Figures 2 and 3, the next incrementof movement will produce a retreat of the needle and a simultaneous rotary or rocking movement of the looper for the purpose of bringing it into the interme diate position shown in Figures 4 and 5. During these operations the turning or rotating movement of the looper rod 19 is transmitted to the shank 25 of the spreader in such a Way that the thread engaging portion ornotch thereof 26 is maintained out of thread engaging relation. However, after the needle has withdrawn to its rearmost position the rotational movement of the looper is reversed and therewith the spreader. But the return n'iovement of the spreader is faster than the movement of the looper so that. as the spreader moves downwardly and rearwardly,

the notch 26 thereof engages the looperthread 6 and continues to depress the same, as indicated in Figures 6 and 7, sufficiently to permit the needle 3 to pass between the looper and the thread. Continued rotational movement or rocking of the spreader, differential in this respect as to movement of the looper, will cause the spreader to disengage from the thread 6 and again assume the position shown in Figures 2 and 3.

From the foregoing description of a sewing machine embodying my invention and from the statement of operation with respect thereto, it will be apparent that the use of .my improved spreader mechanism effects a positive positioning of the looper thread in such a way as to practically insure proper and effective cooperation of the needle therewith so that the dropping or skipping of stitches is reduced to a minimum even when the machine January, 1927.

is operated at maximum speeds. I am aware that spreaders have heretofore been moved in unison with corresponding loopers but I believe that my arrangement of looper and spreader involving a differential movement between said parts is novel and presents substantial utility over the known forms of looper and spreader combinations.

I claim as my invention 1. In a sewing machine the combination of a reciprocatable carrier, a looper rod rockably mounted therein and a loop spreader mounted on said carrier.

2. In a sewing machine the combination of a reciprocatable carrier, a looper rockably mounted therein and a loop spreader mounted on said carrier and havinga rocking motion different from that of the looper.

3. In a sewing machine the combination of a reciprocatable carrier, a looper rockably mounted therein, a loop spreader mounted for rocking movement on said carrier, and means interposed between said loop spreader and said looper for actuating said spreader.

4. In a sewing machine the combination of a reciprocatable carrier, a looper rockablc therein, a bracket on the carrier, a loop spreader having one end journaled in said bracket. a lever securedto said end, a lever secured to the looper, and a link connection between said levers. 5. In a sewing machine, the combination of a looper, means for imparting rocking movement thereto, a spreader, means for imparting co-extensive reciprocative movement [ill to said looper and said spreader, and means for imparting a rocking movement to said spreader different from that of the looper.

6. In a sewing machine, the combination of a reciprocatable carrier, a looper mounted thereon and adapted for rocking movement with respect thereto, and a loop spreader mounted on said carrier for rocking movement relatively to said looper.

In testimony whereof, I have signed my name to this specification this 27th day of MAX KoHLER. 

